Determination of para-Chloroaniline and Reactive Oxygen Species in Chlorhexidine and Chlorhexidine Associated with Calcium Hydroxide

The aim of this study was to determine whether para-chloroaniline (PCA) and/or reactive oxygen species (ROS) are generated by chlorhexidine (CHX) alone or after CHX is mixed with calcium hydroxide at different time points. Mass spectrometry was performed to detect PCA in samples of 0.2% CHX and Ca(OH)2 mixed with 0.2% CHX. High-performance liquid chromatography was used to confirm the presence of CHX in the mixture with Ca(OH)2. The samples were analyzed immediately after mixing and after 7 and 14 days. During the intervals of the experiment, the samples were maintained at 36.5 degrees C and 95% relative humidity. PCA was detected in the 0.2% CHX solution after 14 days. The mixture of CHX with Ca(CH)2 liberated ROS at all time points, but no traces of CHX were present in the mixture as a result of immediate degradation of the CHX. (J Endod 2008;34:1508-1514)

Identity and security in Korea

The summit meeting between the two Korean heads of state, which took place in Pyongyang in June 2000, constitutes a major turning point in the peninsula's history. As the effects of the meeting are gradually unfolding, a period of detente no longer seems impossible. But major difficulties remain unsolved and Korea will continue to be one of the world's most volatile areas. The task of this essay is to identify and analyse some of the entrenched political patterns that will challenge policy-makers in the years ahead. To do so it is necessary to portray the conflict in Korea not only in conventional ideological and geopolitical terms, but also, and primarily, as a question of identity. From such a vantage-point two components are essential in the search for a more peaceful peninsula. Substantial progress has recently been made in the first realm, the need to approach security problems, no matter how volatile they seem. in a cooperative and dialogical, rather than merely a coercive manner. The second less accepted but perhaps more important factor, revolves around the necessity to recognize that dialogue has its limits, that the party on the other side of the DMZ cannot always be accommodated or subsumed into compromise. Needed is an ethics of difference: a willingness to accept that the other's sense of identity and politics may be inherently incompatible with one's own.

Asia Pacific security outlook 2000

Reviews the book 'Asia Pacific Security Outlook 2000,' edited by Richard W. Baker and Charles M. Morrison.

Transmit array of transistor amplifiers illuminated by a patch array in the reactive near-field region

In this paper, a small transmit array of transistor amplifiers illuminated by a passive array of microstrip patches in the reactive near-field region is investigated as a power-combining structure. The two cases considered are when the transmit array radiates in a free space and when a passive array similar to the one used for illumination collects the radiated power. A comparison of the performance of the proposed structure against the alternative one, which uses a conventional horn antenna as a power-launching/receiving device, is also presented.

Securing the commercial internet: Lessons learned in developing a postgraduate course in information security management

This paper describes the inception, planning and first delivery of a security course as part of a postgraduate ecommerce program. The course is reviewed in terms of existing literature on security courses, the common body of knowledge established for security professionals and the job market into which students will graduate. The course described in this paper is a core subject for the e-commerce program. This program was established in 1999 and the first batch of students graduated in 2001. The program is offered at both postgraduate and undergraduate level. The work described here relates to the postgraduate offering. Students on this program are graduates of diverse disciplines and do not have a common e-commerce or business background.

Accumulation of human heat shock protein 60-reactive T cells in the gingival tissues of periodontitis patients

Heat shock protein 60s (hsp60) are remarkably immunogenic, and both T-cell and antibody responses to hsp60 have been reported in various inflammatory conditions. To clarify the role of hsp60 in T-cell responses in periodontitis, we examined the proliferative response of peripheral blood mononuclear cells (PBMC), as well as the cytokine profile and T-cell clonality, for periodontitis patients and controls following stimulation with recombinant human hsp60 and Porphyromonas gingivalis GroEL. To confirm the infiltration of hsp60-reactive T-cell clones into periodontitis lesions, nucleotide sequences within complementarity-determining region 3 of the T-cell receptor (TCR) beta-chain were compared between hsp60-reactive peripheral blood T cells and periodontitis lesion-infiltrating T cells. Periodontitis patients demonstrated significantly higher proliferative responses of PBMC to human hsp60, but not to P. gingivalis GroEL, than control subjects. The response was inhibited by anti-major histocompatibility complex class 11 antibodies. Analysis of the nucleotide sequences of the TCR demonstrated that human hsp60-reactive T-cell clones and periodontitis lesion-infiltrating T cells have the same receptors, suggesting that hsp60-reactive T cells accumulate in periodontitis lesions. Analysis of the cytokine profile demonstrated that hsp60-reactive PBMC produced significant levels of gamma interferon (IFN-gamma) in periodontitis patients, whereas P. gingivalis GroEL did not induce any, skewing toward a type1 or type2 cytokine profile. In control subjects no significant expression of IFN-gamma or interleukin 4 was induced. These results suggest that periodontitis patients have human hsp60-reactive T cells with a type I cytokine profile in their peripheral blood T-cell pools.